Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• distinctive peak at 65.8 ppm in the 19F NMR spectrum (Scheme 3g), which was assigned to phenylsulfonyl fluoride (PhSO2F) [35], a byproduct often obtained in reactions with NFSI [36][37]. Trying to improve the rheology of the reaction mixture and to increase the basicity of the medium, we milled 3a and NFSI in

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• mechanical behavior was studied using rheology. The activation of the supramolecular interactions results in a breaking of these noncovalent bonds, which was investigated using IR spectroscopy, leading to a sufficient increase in mobility and, finally, a healing of the mechanical damage. This scratch-healing

• reported in literature [23]. During cooling, the reformation of the perylene domain was also observed. Finally, P2 featured a second endothermic transition at 13 °C, which is based on the melting of the short PEG-block [24]. Furthermore, both polymers were characterized via rheology and dynamic mechanical

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• interaction of the alkyl chains. Keywords: dirhamnolipid ester; gemini surfactant; rheology; reverse wormlike micelle (RWLM); Introduction Surfactants have both hydrophilic and hydrophobic groups and are therefore amphiphilic molecules. Due to their unique molecular structure, surfactants are essential

• micelles behave similar to a polymer and can be nicely studied by rheology [12][13]. The underlying principle of wormlike micelles, which alter the rheology of the solvent is the same as for the “normal” system (micelles in water). However, the formation of wormlike micelles in organic solvents

• supported by rheological measurements [42] and finally validated by transmission electron microscopy at cryogenic temperature (cryo-TEM) [43]. Temperature-dependent rheology Next, the temperature dependence of the rheology for the RWLM will be described. Oscillatory-shear experiments were performed for the

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• aliphatic chain and on the other side to a glutamic acid residue. The gelator bearing the free carboxylic groups showed a lower gelation capacity than its precursor diester derivative. Some selected gels were further studied by infrared spectroscopy, rheology and electron microscopy. Critical gelation

β-Cyclodextrin- and adamantyl-substituted poly(acrylate) self-assembling aqueous networks designed for controlled complexation and release of small molecules

• Liang Yan,
• Duc-Truc Pham,
• Philip Clements,
• Stephen F. Lincoln,
• Jie Wang,
• Xuhong Guo and
• Christopher J. Easton

Beilstein J. Org. Chem. 2017, 13, 1879–1892, doi:10.3762/bjoc.13.183

• combinations: PAAβ-CDen/PAAADen, PAAβ-CDen/PAAADhn and PAAβ-CDen/PAAADddn separately and when complexing MR, MO or EO form hydrogels, the viscosities of which were determined by rheology. In each hydrogel [β-CDen] = 3.60 × 10−3 mol dm−3 and [ADen, ADhn or ADddn] = 1.20 × 10−3 mol dm−3, the concentration of

• for dye complexation, K11, and the corresponding ΔH and TΔS were derived from the UV–vis data as described in the Results and Discussion section. Rheology Rheological measurements were carried out with a Physica MCR 501 (Anton Parr GmbH) stress-controlled rheometer with a 25 mm cone and plate geometry

A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

• Wangkhem P. Singh and
• Rajkumar S. Singh

Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17

• the gel were carried out using scanning electron microscopy, FTIR spectroscopy, rheology and powder XRD techniques. This gel also showed a good absorption profile for a water soluble dye. Given the non-polar nature of this molecule, gel formation is likely to be mediated by hydrophobic interactions

• spectroscopy, rheology and powder XRD techniques. Based on its absorption profile for a water soluble dye, this gel can potentially be used as a dye removal agent from waste water. The results strongly suggest that hydrophobic interactions alone can mediate gelation of polar solvents and this approach can be

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• just mixing, but also the grinding of the material, which resultantly leads to changes in the material properties, most commonly its rheology [3]. Furthermore, the mechanical energy applied to the system can be controlled by the screw profile, as well as the residence time which is not only dependent

• turn alters the properties of the materials [6]. Initially, the polymer industry employed only batch mixers to synthesise polymers and carry out post synthetic modification (PSM), however, this proved difficult and inefficient. This was due to a dramatic increase or change in the viscosity and rheology

• viscosity, rheology and the kinetics of formation also. The authors report that a reaction between 4,4’-diphenylmethane diisocyanate, polycaprolactonediol and 1,4-butanediol takes place in a twin screw extruder, employing a screw speed of 15 rpm and a temperature of 60 °C [25]. This transformation was

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• isothermal titrimetry calorimetry, ITC [52][70], are frequently used in characterizing host–guest complexation. When viscosity changes occur because of host–guest complexation, rheology may be used to characterize such complexation [71]. Some examples of aqueous polymer systems characterized by these

• polyrotaxanes at low temperature to an elastic hydrogel containing microcrystalline aggregates of the methylated-α-CD components of the hydrogel at higher temperatures using differential scanning microcalorimetry, rheology, X-ray diffractometry and 1H NMR spectroscopy [101]. The average molecular weight of the

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• deriving therefrom include the use as nanocarriers [12][13], electro-optical materials [14], coating additives [15] and rheology modifiers [16]. The link between hyperbranched polymeric materials and linear polymers is represented by star-shaped polymers. This interesting class of polymer architectures can

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• ., acid dissociation constants, isoelectric point and complexation, were investigated by potentiometric titration (pH), nephelometry, rheology and dynamic light-scattering. The formation of pH-responsive interpolyelectrolyte complexes applying polydiallyldimethylammonium chloride was preliminary studied

• titration (pH), nephelometry, rheology and dynamic light-scattering. Moreover, preliminary studies about stimuli-responsive interpolyelectrolyte complexes are presented. Results and Discussion Synthesis The synthesis of a novel polyzwitterion based on cellulose was performed by activation of the polymer

• aqueous solution or the cleavage of carbamate moieties from the polymer backbone during acidic and basic treatment. However, the ratio between amino and carboxylic groups is balanced. In addition, the IP was proofed by rheology. The IP is indicated by a minimum of the relative viscosity of a

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• ; rheology; sulfonamides; Introduction Various diepoxides easily react with amines or diamines to form cross-linked, cyclic or linear addition-polymers, which are implemented in construction, electronic, aerospace, medical and dental industries [1][2]. Hereby, bisphenol A diglycidyl ether (BADGE) is often

Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• mixtures were analyzed by oscillatory rheology and differential scanning calorimetry, whereby significant differences in setting time, viscosity, and stiffness were observed. Keywords: amino acids; curing properties; cyclodextrin; epoxide–amine oligomers; LCST; Introduction Many partially hydrophobic

The conjugation of nonsteroidal anti-inflammatory drugs (NSAID) to small peptides for generating multifunctional supramolecular nanofibers/hydrogels

• Jiayang Li,
• Yi Kuang,
• Junfeng Shi,
• Yuan Gao,
• Jie Zhou and
• Bing Xu

Beilstein J. Org. Chem. 2013, 9, 908–917, doi:10.3762/bjoc.9.104

• nm. These nanotubes form a poorly cross-linked network, which agrees with the instability of the hydrogel of 3g. Rheology Since viscoelasticity is an essential feature of hydrogels [69], we use rheometry to characterize the hydrogels. Based on the stability of these hydrogels, we choose to study the

• rheological properties of the hydrogels of 1a, 1b, 1d, 1f, 2a, 2b, 3a and 4a, and list their rheology data in Table 2. During the dynamic strain sweep, all these hydrogels, under constant oscillation frequencies and different oscillation strains, exhibit a strain-independent storage modulus (G') until

Influence of cyclodextrin on the solubility and the polymerization of (meth)acrylated Triton^® X-100

• Melanie Kemnitz and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2176–2183, doi:10.3762/bjoc.8.245

• ®; randomly methylated β-cyclodextrin (RAMEB-CD); rheology; Triton® X-100 (poly(ethylene glycol)tert-octylphenyl ether); Introduction Triton® X-100 (1) is a macromolecular, nonionic surfactant with an average number of ethylene oxide units of 9.5. The tert-octylphenyl group is a hydrophobic moiety whereas

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• of the PDMS-Im/Br ionic liquid and its mixture with PRot give important information on the interaction between IL and PRot and can explain the dissolution behavior of polyrotaxane in the ionic liquid [28][29][30][31][32][33]. The rheology of the mixture was studied by using both oscillatory and

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

Beilstein J. Org. Chem. 2012, 8, 1318–1332, doi:10.3762/bjoc.8.151

• for the PC/PMMA/PVAc-2 blend. The sample was held for 3 min at 170 °C after the first heating [28]. Storage modulus, loss modulus, and apparent viscosity (G’, G’’, and n*, respectively) for asr- and c-PCL melts, (top and bottom, respectively), as obtained through oscillatory melt rheology (T = 90 °C

Insights into the mechanical properties of a silicone oil gel with a ‘latent’ gelator, 1-octadecylamine, and CO₂ as an ‘activator’

• Emiliano Carretti,
• Mathew George and
• Richard G. Weiss

Beilstein J. Org. Chem. 2010, 6, 984–991, doi:10.3762/bjoc.6.111

• ; gel-sol transition; rheology; viscosity; Introduction During the last two decades, research efforts have increased enormously to understand the range of structures and processes of self-assembly of ‘small’ molecules such as low-molecular-mass organogelators (LMOGs), which gelate large volume

• the SAFIN structures must differ in subtle ways that cannot be understood by rheological measurements alone, but can be sensed acutely by them. Thus, rheology provides an extremely valuable tool to investigate the network structures of gels containing LMOGs. Experimental Dry CO2 gas was bubbled

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• )-(+)-camphoric acid and various secondary amines were prepared based on supramolecular synthon rationale. Out of seven salts prepared, two showed moderate gelation abilities. The gels were characterized by differential scanning calorimetry, table top rheology, scanning electron microscopy, single crystal and

• table top rheology, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), single- and powder X-ray diffraction (SXRD and PXRD, respectively). Single crystal structures of two gelators and one nongelator, i.e., DBUAMC 3, DBAMC 6, and DCHADC 1, respectively were determined and

• transitions occur over a broad range of temperature making it difficult to assess the enthalpy change associated with this process. To get some idea about the enthalpy change associated with gel-sol, we carried out table top rheology [48] on some selected gels (Figure 3). Tgel (gel-sol dissociation